Hamster pulmonary endocrine (PE) cells demonstrate hyperplasia following exposure to diethylnitrosamine which is a systemic carcinogen. A long term selective culture of hamster PE cells was established using defined media. Characterization of these cells show that they share such NE markers (dense core granules, production of peptides calcitonin and bombesin, high levels of dopa decarboxylase and creatine kinase brain isoenzyme) with SCLC and human PE cells. Cultured hamster PE cells will now be used to induce and study malignant transformation of these cells in vitro, as well as the effects of transfecting them with c-myc.